Escherichia coli (hereinafter also referred to as E. coli) is a Gram-negative, short rod bacterium of genus Escherichia, family Enterobacteriaceae, and one of normal flora found in intestines of various animals including mammals. Most strains of Escherichia coli are non-pathogenic and can cause opportunistic infection, but some highly pathogenic strains cause various intestinal diseases and sepsis in animals including humans.
Among these strains of Escherichia coli, avian pathogenic E. coli causes infection through the respiratory tract of birds such as chickens, geese, turkeys, and the like, and is known to pass into the avian body through the respiratory mucous membrane. Avian pathogenic E. coli causes diseases mostly in poultry with respect to respiratory diseases in birds, which leads to enormous economic damage in the poultry industry.
Meanwhile, a bacteriophage refers to a bacterium specific virus that prevents and inhibits growth of a bacterium infected with a specific bacteriophage. As bacteriophages have stronger host specificity than antibiotics, and recent emergence of bacteria resistant to antibiotics and residual antibiotics in animals are growing problems, application of bacteriophages has drawn great interest.
Studies on bacteriophages have been actively performed in many countries, and there has been an increasing tendency to obtain approval from the Food and Drug Administration (FDA) for compositions using bacteriophages in addition to patent applications for bacteriophages.
However, bacteriophage related technologies for prevention and/or treatment of infectious diseases, which are important issues in the aviculture industry including poultry farming, due to avian pathogenic Escherichia coli are still insufficient, and therefore, there is a need for such bacteriophages and development of relevant technologies.